Vulnerability of Antarctic shallow invertebrate-dominated ecosystems

• Published in: Austral Ecology
• Main Authors: Clark, GF, Raymond, B, Riddle, MJ, Stark, JS, Johnston, EL
• Format: Article in Journal/Newspaper
• Language: English
• Published: Blackwell Publishing Asia 2015
• Subjects: Biological Sciences; Ecology; Marine and Estuarine Ecology (incl. Marine Ichthyology); Antarctic; Antarc*; Antarctica; Sea ice
• Online Access: https://doi.org/10.1111/aec.12237; http://ecite.utas.edu.au/105961

Human impacts threaten not only species, but also entire ecosystems. Ecosystems under stress cancollapse or transition into different states, potentially reducing biodiversity at a variety of scales. Here we examinethe vulnerability of Antarctic shallow invertebrate-dominated ecosystems, which may be threatened for severalreasons.These unique shallow-water communities mostly consist of dark-adapted invertebrates, and rely on sea iceto create low-light marine environments. Climate change is likely to cause early breakout of seasonal sea ice in partsof Antarctica, which will dramatically increase the amount of light reaching shallow seabed. This is predicted toresult in ecological regime shifts, in which invertebrate-dominated communities are replaced by macroalgal beds.Habitat for these endemic Antarctic ecosystems is globally rare, and the fragmented nature of their distributionalong Antarctic coast increases their sensitivity to change. Concurrently, human activities in Antarctica areconcentrated in areas where these habitats occur, compounding potential impacts. While there are clear mechanismsof threat to these ecosystems, lack of knowledge about their spatial distribution obscures predictions ofpotential ecosystem loss, and the likelihood of recovery. In this paper we describe these ecosystems, their associationwith the environment and the reasons for their vulnerability.We estimate their spatial distribution around Antarcticausing sea ice and bathymetric data, and apply the International Union for Conservation of Nature Red List ofEcosystems criteria to assess their vulnerability. Best available data suggest that shallow ice-covered ecosystems arelikely Near Threatened to Vulnerable in places, although the magnitude of risk is spatially variable and requiresadditional data to strengthen the assessment.